Preheat oven to 375°F (190°C).
Cook shells until al dente.
Drain and drizzle with olive oil.
In a bowl, combine ricotta and pumpkin.
Add parmesan, egg, and spices.
Mix until creamy and smooth.
In a pan, melt butter and add cream.
Stir in milk and season lightly.
Pour half sauce into baking dish.
Stuff shells with pumpkin mixture.
Arrange shells in the dish.
Pour remaining sauce on top.
Sprinkle mozzarella evenly.
Cover dish with foil.
Bake for 25 minutes.
Remove foil and bake 10 minutes.
Garnish with parsley before serving.